Abstract Despite their natural and societal importance, wetlands are becoming increasingly threatened. The goal of this study is to investigate the potential of polarimetric synthetic aperture radar (SAR) for monitoring one important vegetation constituent of wetlands: Typha. An idealized cylindrical scattering model is developed to portray double bounce microwave scattering from Typha stalks. Then a thin cylinder Brewster angle is introduced; relating the co-pol phase difference (CPD) of Typha to its relative permittivity. Full polarization Radarsat-2 data were acquired for a variety of dates and incidence angle ranges in order to validate the scattering model. The dependence of CPD on incidence angle is found to be consistent with the model. The evolution of CPD with seasonal senescence was also investigated. Despite some agreement with expected trends in vegetation moisture, there are anomalies that remain unexplained; possibly due to ecosystem change. This suggests the need for radar scatterometer experiments in a controlled environment to better explore the dependence of CPD on incidence angle and seasonal change. Last, cross-pol phase difference (XPD) histograms support other research in demonstrating the existence of coherent depolarization in Typha scattering. Additional modeling, entailing the detailed structure of the vegetation, will be necessary to understand this behavior.

中文翻译：

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探索香蒲湿地微波反向散射的偏振相位

摘要 尽管湿地具有自然和社会重要性，但它们正日益受到威胁。本研究的目的是调查极化合成孔径雷达 (SAR) 在监测湿地的一种重要植被成分：香蒲 (Typha) 方面的潜力。开发了理想化的圆柱散射模型来描绘香蒲茎的双反弹微波散射。然后引入细圆柱布儒斯特角；将香蒲的 co-pol 相位差 (CPD) 与其相对介电常数相关联。为了验证散射模型，采集了各种日期和入射角范围的全偏振 Radarsat-2 数据。发现 CPD 对入射角的依赖性与模型一致。还研究了 CPD 随季节性衰老的演变。尽管与植被水分的预期趋势有些一致，但仍有一些无法解释的异常现象；可能是因为生态系统的变化。这表明需要在受控环境中进行雷达散射仪实验，以更好地探索 CPD 对入射角和季节变化的依赖性。最后，交叉极化相位差 (XPD) 直方图支持其他研究证明香蒲散射中存在相干去极化。需要额外的建模，需要植被的详细结构，才能理解这种行为。这表明需要在受控环境中进行雷达散射仪实验，以更好地探索 CPD 对入射角和季节变化的依赖性。最后，交叉极化相位差 (XPD) 直方图支持其他研究证明香蒲散射中存在相干去极化。需要额外的建模，需要植被的详细结构，才能理解这种行为。这表明需要在受控环境中进行雷达散射仪实验，以更好地探索 CPD 对入射角和季节变化的依赖性。最后，交叉极化相位差 (XPD) 直方图支持其他研究证明香蒲散射中存在相干去极化。需要额外的建模，需要植被的详细结构，才能理解这种行为。